1. Field of the Invention
The present invention relates to an electrical connector, and more particularly to an electrical connector for a sheet-like connection member such as a flexible printed circuit or cable (FPC), a flexible flat cable (FFC) and so forth. All of these cables and circuit hereafter will be generally referred to as “FPC” for simplification.
2. Description of Related Art
FPC connectors are roughly classified into two kinds. Typical FPC connectors of the first kind are disclosed in U.S. Pat. Nos. 6,099,346 and 6,755,682, and they generally have a plurality of terminals, and a housing fixing the terminals. Each of the terminals is substantially in the form of a U-shape and mainly composed of a contact beam adapted to contact an FPC, and a pivot beam opposed to and extending substantially parallel to the contact beam. Those U-shaped terminals are side-by-side arranged in the housing and define an open mouth together with the housing between the contact beams and pivot beams thereof for receiving the FPC. The connectors further have an actuator adapted to urge the FPC to connect with the terminals. The actuator is provided with shaft portions each pivotably supported at a free end of the pivot beam and cam portions disposed between the free ends of every two pivot beams. Thus the actuator is rotatable between an open position and a closed position via pivotal engagement of the shaft portions and the pivot beams. When the actuator is at the open position the FPC can be inserted into said open mouth with “zero-insertion force”. When the actuator is rotated to the closed position, the cam portions pressed on the FPC and urged the FPC to connect with the contact beams of the terminals. However, the connection relationship of this kind of FPC connector is not reliable enough because that any unmeant drag or pull incautiously put on the FPC may cause the cam portions to reverse so as to loose the FPC, and therefore the FPC is apt to be dragged out of the open mouth.
There is another kind of FPC connector could well solve the above-mentioned problem. US. Pat. No. 2004/0023551 discloses a typical connector of this kind. The connector comprises terminals each substantially in form of an H-shape. The H-shaped terminal comprises four beams and a fulcrum portion joining the four beams, wherein two opposed beams, both serve as contact beams adapted to contact an FPC, and designated as an upper contact beam and a lower contact beam respectively, and the other two opposed beams respectively serves as a connection beam adapted to be connected to a board and a pressure receiving beam. The terminals are arranged in a housing in a fashion that the two opposed contact beams thereof extend forwards to define an FPC receiving mouth therebetween, and the connection and pressure receiving beams thereof extend rearwards to engage with an actuator. The actuator is provided with oval-shaped shaft portions, functioning as cam portions as well, pivotally moved between the connection and pressure receiving beams of the terminals to urging the two opposed contact beams to clamp the FPC, thereby achieving reliable connection of the connector. The pressure receiving beam is provided with a projection at the tip end thereof for preventing the oval-shaped shaft portion from getting out of the space between the connection and pressure receiving beams.
However, as the shaft portions of the actuator are of oval-shapes, rather than round shapes, they would have a lot of wear during their pivotal movement between the sharp shear edges of the connection and pressure receiving beams of the terminals, especially since the shaft portions are made from resin material whereas the connection and pressure receiving beams of the terminals are made from metal material. The high wear of the shaft portions may disable the actuation function of the actuator and thus can't be ignored. Further, the shaft portion of oval-shape would be angled to wedge up the pressure receiving beam and then escaping out of the space between the connection and pressure receiving beams during initial stroke, or it may become wedged between the connections beam and the projection of the pressure receiving beam, causing binding and/or damage of the actuator. Furthermore, as the terminal must be shaped to provide a relatively large clearance between the connection and pressure receiving beams for the major axis of the oval shaft portion, it cause strength concerns for the design of the pressure receiving beam in lower profile connectors.
Therefore, a new FPC connector is desired to overcome the disadvantages of the prior arts.